Chronometer



Jan. 31, 1961 o. E. BATORI ETAL 2,969,636

CHRONOMETER Filed Aug. 22, 1958 United States Patent O CHRONOMETER Oscar E. Batori, New York, N.Y., and Raymond Nardin, Le Locle, Switzerland, assignors to Batori Computer Company, Inc., New York, N.Y., a corporation of New York, and Ulysse Nardin, S.A., Le Locle, Switzerland, a corporation of Switzerland, jointly Filed Aug. 22, 1958, Ser. No. 756,618

Claims priority, application Switzerland Sept. 23, 19:57

2 Claims. (Cl. 583) The present invention concerns a chronometer which indicates on a single dial at the same time the local time and hour-angle corresponding to the sidereal time and which contains in a single case two spring barrels for two wheel works, a single escape wheel regulating operation of the latter, also indicating members for local time and hour-angle corresponding to the sidereal time which are driven by one of the two wheel works, and finally a kinematic connection between the wheel works which establishes the necessary motional relation between the two indicating members.

The chronometer is characterized in that the above mentioned kinematic connection consists of a differential gear. This differential gear which characterizes the present invention has the advantage of establishing a motional relationbetween the indicating members with a higher accuracy and lower space requirement than it is possible with ordinary gears. An embodiment of the invention is shown in the attached drawing, where:

Fig. l is a top view of the dial and of the indicating members; and

Figs. 2 and 3 are schematic representations of the wheelwork and of the differential gear respectively.

rThe present chronometer indicates at the same time standard and hour-angle corresponding to the sidereal time. The standard time is indicated by the hands 10, 11 and 12, which indicate respectively the 24 hours, 60 minutes and 60 seconds, while the hands 13, 14 and 15 indi- Cate the corresponding hour-angle corresponding to the sidereal time in arc degrees, minutes and seconds.

The chronometer contains two wheelworks, which are driven by two separate spring barrels 16 and 17. The first wheelwork consists of a center wheel 18, a third wheel 19 and a fourth gear 20. The hour hand 10 is rigidly connected with the hour wheel 21, which is driven by the cannon pinion 22 through the motion work 23; the minute hand 11 is carried by the cannon pinion 22. The seconds hand 12 is rigidly connected with the fourth gear 20.

The second wheelwork consists of a center wheel 24 and a third wheel 2S. This wheelwork is connected kinematically with the first wheelwork by a differential gear 26 and a pinion 27 which is secured on the fourth wheel arbor 20a of the first wheelwork.

The motion of the two wheelworks is regulated by a single escapement 28, which is in engagement with the balance wheel 29. The differential gear 26 establishes a kinematic connection of an extremely constant nature between the motion of the indicating members for the standard and sidereal time respectively. This connection, which is represented in detail in Fig. 3, has two coaxial sunwheels 30 and 31, each of which consists of two toothed wheels, also a satellite gear 32 which is held by a plate 33 in mesh with a pinion 34.

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The sunwheel 30 is connected through its wheel 30a with the wheel of the gear 25 and through its wheel 30b with the pinion 32a of the planet pinion 32. The gear 31 is connected through its wheel 31a with the pinion 34, and through its wheel 31b with the wheel 32b of the satellite gear 32. The plate 33 is in engagement both with the pinion 27 and with the pinion 34. The wheel 31a and the plate 33 have the same diameter but their number of teeth differs by one.

The chronometer is also equipped with a hand setting device which is independent of the hands 12, 13, 14 and 1S and which is not represented in detail. Also provided is a mechanism for locking the balance wheel by means of an outside pushbutton (not represented) as well as a winding device for the two spring barrels 16 and 17 by means of a single winding shaft, with the interposition 0f the wheels 35, 36 and 37.

We claim:

1. A chronometer for the simultaneous indication of local time and hour-angle corresponding to the sidereal time, said chronometer comprising a local time assembly and a sidereal time assembly each comprising an individual spring operatively connected to appropriate indicators, escapement means operatively connected to said assemblies, and a differential gear means operatively connected between said assemblies and constructed to impose a predetermined motional relation upon said assemblies respectively corresponding to the difference between local and sidereal time measurements, said differential gear means comprising a pair of planet gears each comprising rst and second gear wheels, the first gear wheel of one of said planet gears being connected to one of said assemblies, a satellite carried by a plate and independently rotatable about its own axis, the second of said gear wheels of both of said planet gears being connected to said satellite gear, said plate being connected to one of said assemblies and to a pinion, said pinion being connected to the rst gear wheel of the other of said planet gears.

2. A chronometer for the simultaneous indication of local time and hour-angle corresponding to the sidereal time, said chronometer comprising a local time assembly and a sidereal time assembly each comprising an individual spring operatively connected to appropriate indicators, a single escapement operatively connected to both said assemblies, and a differential gear means operatively connected between said assemblies and constructed to impose a predetermined motional relation upon said assemblies respectively corresponding to the difference between local and sidereal time measurements, said differential gear means comprising a pair of planet gears each comprising first and second gear wheels, the first gear wheel of one of said planet gears being connected to one of said assemblies, a satellite carried by a plate and independently rotatable about its own axis, the second of said gear wheels of both of said planet gears being connected to said satellite gear, said plate being connected to one of said assemblies and to a pinion, said pinion being connected to the first gear wheel of the other of said planet gears.

References Cited in the le of this patent UNITED STATES PATENTS 2,224,268 McDonald Dec. 10, 1940 FOREIGN PATENTS 225,505 Switzerland May 1, 1943 

